Separable magnet assemblies



July 3, 1962 F. BUDRECK 3,041,697A

SEPRABLE MAGNET ASSEMBLIES Filed Aug. 8, 1960 v 2 Sheets-Sheet 1 gora/Q9.

F. BUDRECK SEPARABLE MAGNET ASSEMBLIES July 3, 1962 Filed Aug. s, 1960 2 Sheets-Sheet 2 United States am I! 3,041,697 SEPARABLE lv/IAGNIl ASSEMBLIES Frances Budreck, Chicago, Ill., assigner to Universal Magnetic Lock, Inc., Chicago, Ill., a corporation of Illinois Filed Aug. 8, 196i), Ser. No. 48,131

5 Ciairns. (Cl. 2l2.01)`

The present invention relates to separable magnet assemblies having parts or `halves which are'releasably held together by magnetic forces. rThe invention is specifically concerned with a separable magnetic connector embodying dual magnets and respective holders therelfor which are so designed that when the two parts are brought into close proximity to each other preparatory to effecting magnetic coupling thereof, the parts are selfaligning and will move into their fully magnetically coupled condition vvith no particular degree of careV being required to effect such alignment. Still more specifically, the invention relates to magnetic connectors utilizing the magnetic properties of ceramic-type magnets and affording for the magnets propena degree of physical shielding and consequent protection against damage.

Ceramic type magnets are a comparatively recent development. Such magnets possess highly improved magnetic and physical properties. For example, among the improved magneticV properties of the ceramic ferrites are the fact that they are very resistant to demagnetization, exhibit small eddy current losses, are electrically nonconductive, `and have high coercive force. Among the physical properties exhibited by suchmagnetic materials are lightness `in weight, increased hardness, and the -fact that magnets constructed of such materialsmay be incorporated in magnet structures which require largernagnetic area with relatively short magnetic length. The

lpresent invention takes advantage of these `desirable features and, in the various embodiments thereof, provides a highly eflicient and lightweight permanent magnet holding assembly having general magnet utility and a wide variety of uses. n f

The separable two-part magnetic connector ofthe pres-` ent invention is versatile in its application and is capable of many uses. describedherein as being -in .the form of aseparableke)l chain connector which is, designed -for'use in'connection with the parking and storage of automobiles and other motor vehicles in public parking lots, garages andthe like. Such separable key chain connectors ordinarily consist of two independent key chains, one of which is 4adapted to retain a single ignition key Vand .the other of which may retain a reserve ignition key and a glove compartment. and trunk-key. The two chains are releasably connected together, usually by ya push-pull snap connec-V tion so thatup'on leaving an automotive .vehicle ina public parking place, the .singleA ignition key maybe left in. the Aignition lock for use by the.. attendant, while the key chain containing `the reserve ignition key and glove compartment. and trunk key may be retained by the vehicle owner. The attendantv is thus precluded from access to either the glove compartment or the trunk, but he `is able to operate v.the vehicle.

The present invention, when put to such use, is designed as an improvement over the magnetic connector, shown .ananescnbed in. United statesmen, No. 2,975,497

granted to `me on March 21, 1961. Whereas, in such patent, one key chain is associatedwith a permanent magnetwhile the other key chain is associated with an arma- Y,ture for the magnet, lin Athe present invention, each key chain is associated with anA individual fmagnet, the two magnets being capable of being magnetically coupled when the parts are assembled and o'f being uncoupledby Vthe exertionV of a moderate degree of manualpull upon The-connector has been illustrated and lof the invention have been shown.

modified form of 'the' connector; and FIG; 6 is a`secti'onal view similar toFIG. 5 showing 3,041,697 Patented July 3, 1962 2 t the two parts. The automobile owner maythus retain either part of theA connector and, regardless of which part he leaves in the ignition lock, he will have at his disposal a small permanent magnet assembly which he lmay use as he sees lit to pick up small magnetic articles such as pins or nails, to test or distinguish ferrous articles or materials from non-ferrous articles or materials, to attach the reserve key chain in a concealed place, as for eX- ample, beneath the cowl or a fender if he does not choose to carry the assembly with him, or otherwise to use the magnet in any manner in which a small permanent magnet may be employed. Whenrthe owner carries the complete coupled connector with him hewill, of course, have at his disposal two such small magnet assemblies, either or both of which may, by separationof the parts, conveniently be attached to a magnetic support wherever such support is available. i

lt is well known that magnetically coupled magnets, whether of the ceramic or other type, may be more readily uncoupled by lateral separation forces than by axial separation forces. Thus, where two magnets having cooperating planar pole faces are employed, in a connector assembly of this general character, there is danger Vof inadvertent lateral separation and consequent loss of one or both par-ts. The present invention obviates this limitation in that means are provided for automatically effecting a mechanical interlock between the parts of the connector when these parts are in their assembled condition, the interlock serving to prevent lateral shifting of thel magnets relative to each other. Two forms of the invention have been illustrated herein and this mechanical interlock is common to both forms. In .one form, the two parts of the connector must be physically separated before the mechanical interlock is destroyed. In the other form, the mechanical interlock is rendered inoperative before physical separation of the parts is effected, thus contributing toward a more facile manual separation of the parts.A Additionally, in this latter form of the invention, means are providedwhereby the manual pulling forces which are applied to separate the parts automatically operate,k first to relatively shift the magnets so that Atheir respective magnetic fieldsdo not appreciably'overlap, thus very appreciably reducing the mutual attractive acter brieiiy Voutlined'above kbeing among the principal objects of the present invention, numerous other ob- `jects and advantages thereof, not at this time enumerated, i will becomereadily apparent as the following description ensues. i

In the accompanying two sheets of drawings for-ming a part of this specification, two illustrative embodiments In these drawings:

' Y FIG. l isa perspective view of a separable key chain assembly embodying a magnetic connector constructed in accordance with the principles of the present invention;

FIG. 2 is a sectional viewtaken substantially centrally and "longitudinally through av preferred for-m of the connector of thepresent invention and showing the two parts thereof assembled upon eachother;

' FIG. 3 is a sectionalview similar to FIG. 2 showing the parts of the' connector separated; v

-fl-TIG. f4! is anexploded'perspective View of the connector'of FIG. 2; FIG. 5 is aV sectional view similar to FIG.' 2 showing the parts of the connectorseparated.'`

j Referring now to thei drawingsln` detailr and in parrfticular to FIGS. l'toS inclusiveQthe preferred form of connector has, for exemplary purposes, been illustrated herein as serving as a key chain coupling device. The connector assembly has been designated in its entirety at and it involves in its general organization two permanent magnet assemblies 12 and 14 respectively. The assemblies 12 and 14 constitute the two parts of the composite connector. The part 14 has associated therelwith a conventional ball and link key chain 16 carrying an automobile ignition key 18, |While the part 12 has associated therewith a similar key chain 20` carrying a reserve ignition key 22 and a trunk lock key 24. As will be described in greater detail presently, the parts 12 and 14,

vwhen disposed in approximate longitudinal alignment ,and

position of close proximitty, are magnetically attracted to each other so that the two key chains 16 and 20l are held together as a unit, but are capable of manual separation merely by pulling the two parts axially away from each other so that the two magnetic ields involved become uncoupled.

The key chains 16 and 20 and the various keys associated therewith are conventional and no claim is made to any novelty associated with the same. Neither is any ,novelty predicated upon the mere attachability of the two key chains inasmuch as separable key cha-ins designed for the same purpose and embodying mechanical spring detent means for'their separation are well known in the art. The invention consists rather in the novel construction, combination, and arrangement of parts of the two parts 12 and 14, these parts having utility in connection with structures other than key chain couplers, for example in refrigerator and -other cabinet door latches.

Referring now specifically to FIGS. 2 and 3, the part 12 is of circular cross section throughout and it includes three principal parts including an outer pole cup in the form of a cup-shaped shell of magnetic material such as mild steel and having a circular end Wall 32 and a peripheral cylindrical side wall 34 presenting a circular open rirn `36. The end wall 32 is formed with a central opening 38 therein and in which opening there is fixedly mounted an attachment `device having an attachment eyelet 42 for the chain 20L The attachment device 40 also serves as a guide post support in a manner and for a purpose that will be made clear presently.

The part 12 further includes a permanent magnet 44 in the form of a relatively thin annular disk having a central opening 46 therethrough. The magnet 44 is magnetized as shown in FIGS. 2 and 3 to provide poles of opposite polarity on the upper and lower magnet faces V48 and 50 thereof. The upper magnet face 48'is cemented Vto Ythe bottom wall 52 of a shallow vcup-shaped retainer 54 of non-magnetic material such as brass, the retainer having a cylindrical side Wall 56 which encompasses the outer cylindrical side 58 of the magnet 44. The central opening 46 in the magnet is concentric with a smaller opening 60 provided in the bottom wall 52 so that a limited region of the bottom wall 52 overhangs the inner periphery of the magnet '44 as shown at 62 in FIGS. 2 and 3. f

The attachment device 40 is in the form of a specially constructed shouldered rivet having a shank portion 70 yand `a head portion 72, the eyelet 42 being formed on the head portion. The shank portion 70 extends through vand .is xed in the opening 38 in the bottom wall 32 of the ,pole cup 30. A guide sleeve 74 surrounds the shank portion 72 of the device 40 and, in the assembly of the unit 12, the `free end of the shank portion 70 and adjacent rim of the sleeve 74 are riveted as shown at 76 to provided an outwardly turned retaining flange on the sleeve and also to anchor the sleeve in position against 4"the bottom wall 32 of the'pole cup 30. The shank portion 70 and sleeve 74 constitute, in effect, a composite Vguide'post on which the magnet 44 -is slidable axially for purposes that will appear presently.

The magnet 44, Vtogether with its 'non-magnetic retainer '54 yare slidable bodily Vas a unit'and axially within the pole cup 30 between the retracted position wherein it is shown in FIG. Z where the bottom Wall 52 of the retainer 54 is in face-to-face coextensive engagement with the bottom wall 32 of the pole cup, and the advanced lposition wherein it is shown in FIG. 3 where the overhanging portion 62 of the retainer 54 engages the outturned flange 76. In the retracted position of the magnet 44, the plane, of the pole face 50 lies inwardly of the pole cup rim and in the advanced position of the magnet, the plane of the pole face 50 projects a slight distance outwardly beyond the rim 36 to form a lateral interlock with the part 14 as will be described subsequently.

Still referring to FIGS. 2 and 3, the part 14 is ofk circular cross section throughout and it includes two principal parts including a magnet 80, which may be identical with the magnet 44, and a fixed pole cup 82 therefor and which .may be identical with the pole cup 30. The magnet is provided with pole^faces 84 and 86 of opposite polarity and the pole face-84 is cemented to the bottom wall 88 of the pole cup 812. The plane of the pole face 86 lies -within the confines of the pole cup 82, and inwards of the rim 89 of the side wall 90 of the pole cup 82.

An attachment device 91 is ixedly secured within an opening 92 provided centrally in the wall 88 by a riveting operation as shown at 94 and has an attachment eyelet 96 associated therewith. The magnet 80 -is provided with a central opening 98 which provides a clearance for the riveted portion '94 of the device 91.

In the utilization of the connector 10 just described for `any of the various purposes of which it is capable of serving, when the parts 12 and 14 are separated as shown in FIG. 3, the bottom wall 32 of the pole cupl 30 serves, in effect, as an armature and is attracted to the magnet pole face 48, thus drawing the magnet to its retracted position wherein the plane of the pole face 50 lies inside the rim 36 and is thereby shielded to a `certain extent against inadvertent contact with extraneous objects. In bringing the two parts 12 and 14 into axial alignment and positions of proximity as shown in FIG. 3 for the purpose of coupling the parts magnetically, as soon as the fields offered by the pole faces 50 and 86 become magnetically coupled, the greater mutual attraction between these two pole faces overcomes the lesser attraction of the pole face 50 for the bottom ywall 32, which exists due to the slight separation offered by the thickness of the Wall 52 of the retainer, and the magnet leaves this bottom Wall and is projected to its advanced position as shown in FIG. 3 wherein a portion of the magnet is projected outwardly beyond the rim '36 of the pole cup 30 and wherein rthe pole face 50 is attracted to and engages the pole face 86 of the magnet 80;. Thus, when the two parts 12 and 14 are moved to their finally coupled positions, this projecting portion of the magnet y44 extends against lateral separation. The cylindrical side Wall 56 of the retainer 54 serves the dual function of providing a sliding t for themagnet Within the pole cup 30 and of projecting the ceramic material of the magnet against chipping or fracture by the rim portion of the side wall 90 -when forces `tending to misalign the pole cups 30 and 82 are applied.

Referring now to FIGS. 5 and 6 wherein `a slightly different form of connector 100 has been illustrated, the connector including two parts 112 and 11-4 respectively, the part 112 'being similar to the part 12 and the part 114 being substantially identical with the part 14. Be-

cause of the similarity of parts, and to avoid needless repetition of description, reference numerals similar to those employed in connection with FIGS. 2 and 3, but of a higher order, have been applied to the corresponding v parts in FIGS. 5 and 6.

In this form ofthe invention, the sleeve 74 has been omitted from the attachment device `and the shank portion of the same is loosely projected through theV lopening 138 in the bottom wall 132 of the pole cup 130.

Otherwise, the .corresponding parts as shown between the j structures of FIGS. Zand 3, `and 5 and 6 respectively remain the same.

,In the operation of the form of the invention shown in FIGS. 5 and 6, when the parts are assembled upon each otherV as shown in FiG. 5, the mutual attraction between the two magnets 1S@ and 144 not only draws the two magnets together, but the magnet 144 draws the attachment device 14th forwardly so that the head portion 172 of rthe device 140 seats upon the outer face of the bottom wall 132 of the pole cup 130. Conversely, when `axial pull is initially applied relatively to the parts 12 and 14 in a direction tending to separate them, the magnet 144 is withdrawn. into the contines of the pole cup 130 before any axial pull is applied to the latter. The magnetic iields of the two magnets 144 4and 180 are thus at least partially uncoupled so that only a very, small degree of pull is required to movethe pole cups 190 and 134 apart. While there may remain some degree of at-` traction between the rims of the two pole cups 19t?` and 134, the formerly existing mutual attraction between the two magnetv pole faces l150 and 136 has been destroyed, thus materially relieving the overall attractive power of the parts 112 and 114. Furthermore, because of the fact lthat the magnet 144 is fully withdrawn into the pole cup 130, the lateral interlock formerly existing between the parts is destroyed. The parts may thus be pulled apart either in an axial direction or laterally.

It is to be noted that, in either illustrated form of the invention, when the two parts of the connector are assembled with the rims of the pole cups in contact and register, the opposed pole faces of the two magnets are inV mutual coextensive face-to-face contact. Ordinarily due to the high coercive force of ceramic vtype magnets, an extremely high degree of mutual attraction between the two magnets would be required to separate them. However, in the present assemblies, the magnetic eld surrounding the magnets is concentrated in the metal of the two pole cups, thus relieving to a large extent the direct magnet-to-magnet pull. Then after the initial pull onthe devices has eifected magnet separation as previously described, the attraction exerted by the two pole cups upon each other is materially relieved so that separation of the two parts or assemblies may be effected without requiring an inordinate -degree of manual force.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit of the invention. Only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention `what Iclaim as new and desire to secure by Letters Patent is:

l. As a new article of manufacture, a two-part magnetic connector comprising iirst and second magnet assem- V blies, each assembly including a permanent magnet of the ceramic `type and in the form of a flat disk presenting oppositely facing pole faces and a narrow continuousk spencer assembly being slidable back and forth between a re-v tracted position wherein it is disposed wholly within the connnes of its pole cup and with one pole face there-v of attracted to the bottom wall of its said pole cup, and an ladvanced position wherein, when the assemblies are coup-led, the other pole face thereof projects beyond the rim of the side walls of its respective pole cup and is `attracted-to the' adjacent pole face of the magnet of the second assembly to the end that the magnet of the tirst assembly coacts Withrthe side wall of the pole cup of the second `assembly to hold the two assemblies -against relative lateral displacement, andV spacer means positioned between said one pole face and the magnet of the rst assembly and the bottom wall of the pole cup of such assembly for limiting the extent of magnetic attraction between such pole face and bottom wall to a value below that of the magnetic attraction between the adjacent pole faces of the two magnets when the two assemblies are coupled. y

2. A two-part separable magnetic connector as set forth in claim l andwherein said spacer means comprises ka retainer of` non-magnetic material having a flat thin wall portion in face-to-face contact with said one pole face of the, magnet of the first `assembly and movable bodily with such magnet into and out of engagement with thebottom wall ofthe pole cup of the iirstmagnet assembly.

3. As a new article of manufacture, a two-part separable magnetic connector comprising first and second magnet assemblies, each assembly including a permanent magnet of the ceramic type and in the form of a at of relatively large width and short height, said diskpresenting oppositely facing pole faces, each -assembly also including a pole cup of magnetic material, having a bottom wall and a continuous side wall presenting an open rim extending closely around the side face of the magnet, and within which the magnet is nested, the'magnet of each assembly being of less height than the side -wall of its respective pole cup, the magnet of the first assembly being provided with a central opening therethrough, a guide post projecting axially through a hole in the central porside face, and a pole cup of magnetic material, having f a bottom wall and a continuous side wall presenting an open rim and extending closely around the side face of the magnet, the over-all extents of the side walls of the pole cups of the two assemblies being substantially equal in order that the two assemblies may be coupled by positioning them with the rims of the sidewalls of the pole cups in edge-to-edge relationship, the magnet of each assembly being of. less height than the side wall of its respective pole cup, the magnet of the second assembly 'being fixed within its respective pole cup in such manner that its outer pole face lies in a plane spaced a slight distance from the plane of the open rim of the side wall of its pole cup, the magnet of the first assembly being provided with aV central opening therethrough, a guide post carried by the pole cup of the iirst assembly and projecting into said opening, said magnet of the first tion of the bottom wall of the pole cup` of the first assembly Vand slidable axially with respect to said bottom wall, said guide post projecting into said opening in the magnet of the first assembly and provided at its forward end with a radial ange for preventing removal of the magnet from the guide post, said magnet of the iirst 'assembly being slidable bodily back and forth between a retracted position wherein it is disposed wholly within the contines of its pole cup, and an advanced position Whereinfone pole face thereof is projected beyond the open rim of the side walls -of its pole cup, the magnet of the second assembly being xed, lying wholly within the confines of its respective pole cup, and presenting a pole face in a plane spaced aslight distance from the plane of the open rim of the side wall of its pole cup, the rims of said side Walls being substantially of the same size and shape in order that said rims may be positioned in coextensive edge-to-edge relationship when the two assemblies of the connector are coupled, the magnet of said rst assembly being adapted, when the twoV assemblies are arranged in coupled relationship, automatically to slide linto its advanced position to the end that the portion thereof with said one pole face is disposed within the sidewall of the pole cup of the second assembly and coacts therewith to hold the two assemblies against relative later-al displacement, and spacer means positoned between the other pole face of the magnet of the rst assembly and the bottom wall of the pole cup of such assembly for limiting the extent of magnetic attraction between said other pole face and bottom wall to a value below that of the magnetic attraction between the adjacent pole faces of the two magnets when the two assemblies are coupled.

4. Asa new article of manufacture, a two-part sepa- 'rable magnetic connector comprising first and second magnet assemblies, each assembly including a permanent magnet of the ceramic type and in the form of a flat disk presenting oppositely facing pole faces and a narrow continuous side face, and a pole cup of magnetic material, having a bottom wall and a continuous side wall presenting an open rim and extending closely around the side face of the magnet, the over-all extents of the side Walls of the pole cups of the two assemblies being substantially equal in order that the two assemblies may be coupled by positioning them with the rims of the side walls of thev pole cups in edge-to-edge relationship, the magnet of Y each assembly being of less height than :the side wall of its respective pole cup, the magnet ofthe second assem- =bly being fixed within its respective pole cup and positioned so that its outer pole face lies in a plane spaced a slight distance inwards from the plane of the open rim of `the side Wall of its pole cup, the magnet of the rst assembly being movable bodily back and forth between a retracted position wherein it is disposed wholly within the confines of its pole cup and with one pole face thereof attracted to the bottom wall of its said pole cup, and an advanced position wherein, when the two -assemblies are coupled, the other pole face thereof projects beyond the rim of the side wall of its respective pole cup and is at- 2 tracted to the adjacent pole face of the magnet of the second assembly to the end that the magnet of the first astive lateral displacement, the bottom wall of the pole` cup of the lirst assembly having a hole in its central portion, and a member extending slidably through said hole,

koperatively connected to the magnet of said first assembly, and adapted when pulled away from the bottom wall` of the pole cup of the rst assembly while the two assemblies are in their coupled relationcto move, the magnet of the first assembly into its retracted position andV thus release the two assemblies for manual separation.

5. A two-part separable magnetic connector as set forth in claim 4 and including', additionally, spacer means positioned between said one pole face of the magnet of the first assembly and the bottom wall of the pole cup of said assembly and operative to limit the extent of magnetic attraction between such pole face and bottom wall to a value below that of the magnetic attraction between the adjacent pole faces of the two magnets when the two assemblies are coupled.

References Cited in the le of this patent UNITED STATES PATENTS 2,281,204 Raymond Apr. 28, 1942 2,288,688 Dubilier July 7, 1942 2,475,226 Ellis July 5, 1949 

